A user attending an audio/video event may need help allowing him/her to better understand that event. For example, if the audio/video event is a movie, the user may need subtitles or a spoken description of the event, a visual description of the event in the sign language or other audio/video information related to the event. The user can load into a portable electronic device provided with a display and/or a speaker, e.g. a mobile phone or smartphone, at least one audio/video file corresponding to said help, however this may be difficult to synchronize with the event, especially if the event includes pauses or cuts, or if the audio/video file is read after the event has started.